Prostate cancer patients can be treated using a procedure known as brachytherapy. In a brachytherapy prostate procedure, tiny pellets or “seeds” of a highly radioactive material such as Palladium 103, Iodine 125, or Iridium 192 are implanted directly into or adjacent to the cancer tumor using needles. The radiation may be delivered by permanent low dose rate seeds placed through open-ended interstitial needles. Alternatively, radiation may be delivered by temporary high dose rate (HDR) seeds using closed-ended needles, a procedure that does not leave the patient radioactive. The radiation from the seeds is absorbed within a small area (the Greek term “brachy” means short distance), and therefore destroys cancer cells in the prostate without adversely affecting large areas surrounding the tumor. In certain cases, this radiation delivery method is preferable to treatment using external beam radiation in which the radiation is not localized and can result in damage to healthy tissue and limited radiation delivered to the tumor.
In the general steps of performing HDR brachytherapy, the thin needles are first placed in or around the tumor. The needles are then connected to a device called an HDR afterloader, which is a computer-controlled machine that protectively houses a single high intensity radioactive seed source. The afterloader inserts the seed source on the end of a wire through a transfer tube and into the closed-ended needle. The wire is then paused at multiple dwell positions to apply dosage in accordance with a dosage plan. The radioactive seed source is then withdrawn by the wire to the protective housing of the afterloader. This procedure is then repeated for some, or all, of the remaining delivery needles depending on the dosage plan.
There is a complicating factor in HDR brachytherapy for prostate cancer. The insertion of the brachytherapy needles is done with the patient lying on his back on a procedure table or hospital bed with his legs elevated in stirrups. Following needle placement, the patient is moved to a different room, sometimes even a different medical facility, where a CT scanner is used for imaging the tumor and needles to create a computerized dosage template for delivery of the radioactive seeds. The patient is then moved from the CT scanner to yet another location with an HDR afterloader for delivery of the radiation dose based on the computerized template. The movement of the patient during the entire procedure may require transfer from the procedure table for the needle insertion to a gurney and/or ambulance for transport to the CT scanner, transfer to a radiolucent platform for the CT imaging, and then further transfers from the radiolucent platform to a gurney and/or ambulance to the HDR facility and to the treatment platform for the dosage delivery.
This repeated transfer and transport of the patient may cause displacement or even dislodgement of the needles, resulting in uncertainty regarding the proper positioning of the needles when they are presented to the HDR afterloader. Since the computerized dosimetric plan was based upon the needle placement as imaged at the CT scanner to deliver precision dosage to specific locations, any movement of an interstitial treatment needle between the CT imaging and the radioactive seed insertion will degrade the level of precision.
Despite this need to keep the needle placement constant, it is normal practice to place a patient's legs in a lowered position as he lies on his back for transfer and transport. This too often causes the inserted needles to be pulled downwardly by folds of tissue in the pelvic area or to be moved by contact with the mattress on the gurney or ambulance stretcher. Such needle movement increases the uncertainty regarding needle positioning. Such needle movement can also be uncomfortable for the patient and can possibly lead to relatively serious injury.
In recognition of these problems, I have developed a portable patient support device, as described below. Although the device is configured for effective use in preparing a patient for prostate HDR brachytherapy, and its use described in relation to that procedure, it should be noted that the device can be configured for other procedures, either other radiotherapy procedures such as radioactive material implantation of the cervix and uterus or for immobilization and transportation of neurosurgery or orthopedic surgery patients.